Seven fishes must be a recurring theme across cultures.
The British Stargazy Pie (big sardines) came out of a tradition that a lone fishing boat from a starving village put out to sea in a storm around Christmas, and was able to haul in a catch large enough to feed the village, and that there were seven different types of fish in the catch.
Your post caused me to wonder about the word/number ‘seven’; and I found this:
https://mysticalnumbers.com/number-7/
(For what it’s worth :-)